1. Field of the Invention
The present invention generally relates to backlight control, and more particularly to a backlight control system and method using an overdrive lookup table.
2. Description of the Prior Art
Backlight is used to illuminate a flat panel display, such as a liquid crystal display (LCD), from the back or side of the flat panel display. The light source may be a cold cathode fluorescent lamp (CCFL), a light-emitting diode (LED) or another light source.
A constant backlight is the backlight that outputs even and constant light no matter how the image data or the ambient light has been changed. The constant backlight approach has poor dynamic contrast. In order to increase the contrast, a dynamic backlight (DBL) is thus disclosed to dynamically or adaptively adjust (overall or respective portions of) the backlight brightness in accordance with image data distribution.
Nevertheless, a normal cold cathode fluorescent lamp (CCFL) has a low response time. In other words, the CCFL requires a period of time to reach target brightness, and therefore the change of brightness of the backlight usually lags behind changes in the backlight driving signal, such as a pulse-width-modulation (PWM) duty signal. The low response-time problem may only be solved by replacing the normal but low-price CCFL with a fast-response but expensive CCFL. However, such solution is not practical to mass production considering the cost and the acceptance of general users.
For the reason that conventional backlight, particularly the dynamic backlight, could not effectively respond conforming to the requirement, a need has arisen to propose a novel dynamic backlight control scheme having faster response time without sacrificing the cost.